Hello, Philip.
About 20 years ago, I inherited a process to tin dip component leads. I used
an agressive water soluble flux and finished with water wash and a
neutralizer. The component leads were dipped in a still pot. Emmersion rate
and pot temperature were controlled variables. I had two problems. The first
was that the high volume of parts to be coated caused intermetallic needles
to appear in the plate within a few days operation. Needles could be
temporarily controlled by lowering pot temperature just above melting point
and scooping out precipitated needles. This was a major nuisance and left
the pot near saturation. Steam floatation was recommended but proved too
dangerous for production. As I recall we were coating about 4 million
leads/week (about 670,000 wire feet)in a 200 lb pot. Much too small.
The second problem, which was of lesser consequence was that the coating was
uneven on the wire. Thickness ranged from maybe 50 micro-in to 2 mils on the
same wire. The geometry of the parts was ideal and no experimentation with
process parameters solved the problem. An associate reported the same
results in previous attempts to coat this way. I don't recall solderability
problems reported for components after storage but then customers had lower
expectations for solderability at that time.
Hope this is of some benefit.


-----Original Message-----
From: Philip Adamson [mailto:[log in to unmask]]
Sent: Wednesday, August 29, 2001 6:28 AM
To: [log in to unmask]
Subject: [LF] Lead-free Solder Dip


All

does anybody have any experience of changing over from tin/lead solder dip
to a pure tin solder dip for through-hole discrete components? Are there any
major problems associated with this? I would be interested to hear any
comments people have.

thanks and regards

Philip Adamson
Development Engineer
International Rectifier GB

----------------------------------------------------------------------------
-----
Leadfee Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop delivery of Leadree for vacation breaks send: SET
Leadfree NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
----------------------------------------------------------------------------
-----


The information contained in this email message may be privileged and is
confidential information intended only for the use of the recipient, or any
employee or agent responsible to deliver it to the intended recipient. Any
unauthorized use, distribution or copying of this information is strictly
prohibited and may be unlawful.

If you have received this communication in error, please notify the sender
immediately and destroy the original message and all attachments from your
electronic files.

---------------------------------------------------------------------------------
Leadfee Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------